As will be appreciated by those skilled in the art, radiation therapy treatment for extracranial malignancy is trending toward fewer radiation fractions and higher doses per fraction over shorter periods of time. This is occurring because of theoretical advantages in the effect on tumor biology and both economic and social advantages related to a shorter treatment period and fewer trips to the clinic. This modality has been enabled by tremendous improvements in imaging with better tumor definition and visualization of surrounding structures combined with advances in linear accelerator (LINAC) beam targeting and dose painting technologies. The devices and methods of treatment required to accomplish this are collectively referred to as stereotactic body radiotherapy (SBRT). Previously, stereotactic radiotherapy has been applied mainly to brain tumors and often has been reduced to a single, high dose, precisely targeted treatment using an external frame that is bolted to the skull, so called stereotactic radiosurgery (SRS). Stereotaxy may be defined as the three dimensional spatial localization targeting of an object by using its known measured relationship to an adjacent set of objects. The objects in known relative position may be located in an external frame that is fixed in relation to the tumor as has historically been done for SRS, or may be any set of reference points having a known physical relationship to the target that may be available, so called “frameless stereotaxy”.
SBRT is a new and rapidly developing area of cancer management. Consequently, the devices and methods that support it are not yet optimized or widely shared, and many different paths have been taken.
Patient positioning is a prime example. Some investigators feel that extremely precise and reproducible patient positioning is critical, whereas others believe that frequent re-localization of the target with imaging is more important. Some centers have invested in robotic LINACS that will move the beam to track a moving target, whereas others have invested in patient positioning and immobilization systems that restrict movement of the target tumor by restricting respiratory movement of the chest wall and/or diaphragm. Several device manufacturers have developed individual solutions for one camp or another. All parties are in agreement that keeping the patient as still as possible when the treatment beam is on, within some boundaries of comfort and the physiological processes that are required to sustain life, is highly desirable.
Patients undergoing SBRT typically are disposed on a treatment couch or table associated with LINAC or other the radiation therapy apparatus. Various couchtops and overlays are commercially available for disposition on the treatment couch, with the patient being disposed on the couchtop/overlay. As is known an overlay is disposed on top of the cradle, existing support frame and/or spine of a CT, simulator or LINAC. For SBRT applications it is a common practice to position and fix a portion of the patient so that repeated treatment can be given to the patient. To that end, some indexing system is provided for mounting and positioning various patient positioning and/or fixation devices on the couchtop or overlay at predetermined positions with respect to the couchtop/overlay. Examples of such patient positioning/fixation devices are head and neck positioning/fixation devices, breast and thorax positioning/fixation devices, and hip and pelvic region positioning/fixation devices. Many of such devices, as well as other miscellaneous positioning aids, e.g., cushions, wedges, etc., for use on the treatment couchtop/overlay are available from the assignee of this invention, Civco Medical Solutions (hereinafter “CIVCO”), and are shown in its “Radiation Oncology Sourcebook”© 2007.
The treatment couchtops/overlays available from CIVCO make use of an array of equidistantly spaced indexing points running down the side of the couchtop/overlay. A two-pin LOK-BAR™ also sold by CIVCO is arranged to be connected to the couchtop overlay at any of the indexing points. The two-pin LOK-BAR™ is an elongated bar that includes two pins projecting upward from it to interface (be received in) corresponding holes on CIVCO's line of patient positioning and fixation devices. To index a particular positioning/fixation device to the couchtop or overlay the LOK-BAR™ is attached to the couchtop or overlay via any of the multiple indexing points. The particular patient positioning/fixation device is then mounted on the LOK-BAR™ by disposing it on the LOK-BAR™ so that the two-pins of the LOK-BAR™ are received within corresponding apertures in the positioning/fixation device. By indexing the patient positioning/fixation device(s) to the same indexing points for every radiation treatment one can be assured of increased target accuracy and patient throughput.
Other manufacturers also provide couchtops/overlays with indexing systems and positioning/fixation devices to be used with such indexing systems. While there are devices that are commercially available to perform a specific method of patient positioning and/or immobilization and there are specific devices designed for various niche approaches to SBRT, what is missing is a general solution for immobilizing patients that is sufficiently versatile to have broad appeal to multiple centers doing SBRT. In short, what is needed is an integrated solution that allows the user to tailor the positioning and immobilization methods to suit the patient, their LINAC (or other therapy apparatus) and their treatment plan.
The present invention addresses that need by providing a system for reproducible patient positioning and immobilization during SBRT. In particular, the system makes use of a modular design that allows a broad range of established positioning and immobilization techniques to be applied as needed. Patient comfort, setup time and patient transportation are optimized. The system basically comprises a portable platform (referred to as a patient support panel) having a pair of rails that enable full indexing of various components used during SBRT along its length. Those components also form part of the subject system and include modular multifunctional bridges and other positioning/fixation components and other components/accessories that may be positioned anywhere along the length of the platform to be used to position/fix the patient or provide any other function desired during SBRT treatment. The multifunctional bridges are particularly significant in that they can be positioned where needed to provide various types of immobilization, hold instrumentation or enable stereotactic frames or other positioning and localization devices to be used.
Those bridges, the patient support panel and the other modular accessories/component of the subject invention will be described in detail later. Suffice it for now to state that they allow the user to apply any of the full range of positioning and immobilization techniques that are in current use for SBRT. And, this is accomplished with the likelihood of greater comfort for the patient and ease of use for the therapist. The patient support panel accommodates standard stereotactic frames or frameless approaches to treatment. In addition, the patient support panel is designed to be transportable with the patient immobilized on it. Thus, workflow may be improved by allowing time consuming patient setup to be completed outside the expensive LINAC room and then have the SBRT platform precisely positioned on the standard LINAC treatment couch. Alternatively, the patient support panel with the patient immobilized on it could be transferred to an imaging device such as a CT or MR scanner to update targeting data prior to therapy and then be transferred to the LINAC couch without movement of the patient in relation to the platform.
All references cited and/or identified herein are specifically incorporated by reference herein.